Go to the Applications page on face book, however over Applications, click on "See All My Applications." Then on the left-side module, click on "All Applications." You can edit settings for each application by clicking on the blue pencil icon to the right of the application name. From there, you can choose to add or remove an application from the Boxes tab.
Click on "Edit Settings"
Click on "Profile"
Click on "Add" next to Box: Available
-Click on "Edit Settings"
-Click on "Profile"
-Click on "Remove" next to Box: Added